/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.activiti.engine.impl.cmd;

import java.io.Serializable;

import org.activiti.engine.ActivitiException;
import org.activiti.engine.ActivitiObjectNotFoundException;
import org.activiti.engine.form.TaskFormData;
import org.activiti.engine.impl.form.FormEngine;
import org.activiti.engine.impl.form.TaskFormHandler;
import org.activiti.engine.impl.interceptor.Command;
import org.activiti.engine.impl.interceptor.CommandContext;
import org.activiti.engine.impl.persistence.entity.TaskEntity;
import org.activiti.engine.task.Task;

/**
 * @author Tom Baeyens
 */
public class GetRenderedTaskFormCmd implements Command<Object>, Serializable {

    private static final long serialVersionUID = 1L;
    protected String taskId;
    protected String formEngineName;

    public GetRenderedTaskFormCmd(String taskId, String formEngineName) {
        this.taskId = taskId;
        this.formEngineName = formEngineName;
    }

    @Override
    public Object execute(CommandContext commandContext) {
        TaskEntity task = commandContext
                .getTaskEntityManager()
                .findTaskById(taskId);
        if (task == null) {
            throw new ActivitiObjectNotFoundException("Task '" + taskId + "' not found", Task.class);
        }

        if (task.getTaskDefinition() == null) {
            throw new ActivitiException("Task form definition for '" + taskId + "' not found");
        }

        TaskFormHandler taskFormHandler = task.getTaskDefinition().getTaskFormHandler();
        if (taskFormHandler == null) {
            return null;
        }

        FormEngine formEngine = commandContext
                .getProcessEngineConfiguration()
                .getFormEngines()
                .get(formEngineName);

        if (formEngine == null) {
            throw new ActivitiException("No formEngine '" + formEngineName + "' defined process engine configuration");
        }

        TaskFormData taskForm = taskFormHandler.createTaskForm(task);

        return formEngine.renderTaskForm(taskForm);
    }
}
